The tables are compiled in association with EducationGuardian.co.uk by Campus Pi, an applied research department at Brunel University. The rankings are compiled from the most recent figures available - official 2005-06 returns from universities and higher education colleges to the Higher Education Statistics Agency (Hesa). They also incorporate data from the National Student Survey (NSS) 2006, published by the Higher Education Funding Council for England.

Checking our ﬁguresTwo checks with academic institutions have taken place. One in December-January for feedback on subject areas listed for institutions and how subjects should be matched to cost centres. Subsequently Hesa asked institutions to check the data supplied to the Guardian.

We have used seven statistical measures to contribute to the ranking of a university or college in each subject, weighted as follows:· Teaching quality - as rated by graduates of the course (10%)· Feedback - as rated by graduates of the course (5%)· Spending per student (17%)· Staff/student ratio (17%)· Job prospects (17%)· Value added - comparing students' degree results with their entry qualifications (17%)· Entry score (17%)

We don't publish the actual figures for spending, entry qualifications etc. Scores are marked out of 10 in bands, in order to compare like with like - spending on medical students is bound to be higher than on business students. In response to requests from institutions we are publishing a breakdown of the figures used for each band in each subject and the number of institutions in each band (for dedicated stats fan only).

For each subject that it teaches, an institution is given a Guardian score, based on these seven measures. The Guardian score for each institution in each subject is derived from a weighted average of the standardised scores for each measure, converted into a scale in which the highest ranked institution gets 100 points and all institutions receive a positive score.

When it comes to the overall score for a university, the subject scores are weighted according to the number of first degree students enrolled on the course - a department with 200 students counts more than one with 50.

We do not include research ratings or research funding - these are tables aimed at first degree students and so concentrate on teaching and teaching resources.

ThresholdsTo be included in a subject table an institution must be teaching at least 35 students (full-time equivalent or FTE) - with at least 25 FTE reported in the relevant cost centre.

Also excluded are institutions where data for more than two measures are missing. (The NSS scores are counted as one for this purpose.) The process for dealing with the missing data is to subtract the weight of the missing items from 100%, and divide the weighted average of the standardised scores by this figure. In effect, this methodology assumes that the institution would have performed equally well in the missing data items as it did in the measures for which its data was available.

We have also imposed a threshold on the overall universities table - an institution must feature in at least five subject tables. This excludes a number of specialist colleges - in music, for instance - who may be at the top of their subject rankings.

On the university ranking table, the following institutions do not have scores because they appear in fewer than five subject tables: Arts Institute, Bournemouth; Bishop Grosseteste UC; Buckingham; Central School of Speech and Drama; Courtauld Institute; Cumbria Institute; Dartington College; Edinburgh College of Art; Glasgow School of Art; Leeds College of Music; Norwich School of Art; Ravensbourne College; Rose Bruford College; Royal Academy of Music; Royal Agricultural College; Royal College of Music; Royal Northern College of Music; Royal Scottish Academy of Music and Drama; Royal Veterinary College; Royal Welsh College of Music and Drama; School of Pharmacy; Scottish Agricultural College; St George's Medical School; St Mary's UC, Belfast; Stranmillis UC; Trinity Laban; UC Falmouth; University College for the Creative Arts; UHI; Writtle College.

The measuresTeachingFor the first time we have used results from the NSS, carried out for the second time in 2006, which questions final year undergraduates about what they think of the quality of the course.

We take the average response of students (which are on a Likert scale and calculated for populations of 10 and over). The survey was published in fairly broad subject categories - biology, physical sciences and so on - but we hope Hefce will in the future make more fine-grain results available.

We used the responses to four questions in the NSS under the heading of the "teaching on my course": staff are good at explaining things; make the subject interesting; are enthusiastic about what they teach, and the course is intellectually stimulating.

FeedbackThis score derives from answers to five questions on feedback relating to whether marking criteria were made clear in advance, assessment arrangements were fair, feedback was prompt, whether they received detailed comments on their work and whether feedback "helped me clarify things I did not understand".

Spending per studentThe amount of money that an institution spends providing a subject (not including the costs of academic staff, since these are already counted in the Staff/student ratio) is compared with the volume of students learning the subject to derive a spend per student measure. This figure also includes the money the institution spends on central academic services, also per student FTE.

Staff/student ratio (SSR)SSRs compare the number of staff teaching a subject with the number of students studying it, to get a ratio where a low SSR is treated positively in the league tables. At least eight students and three staff (both FTE) must be present in an SSR calculation.

This is far from being as straightforward as it sounds because the subjects taught do not relate neatly to cost centres in universities and a lot of effort by the Guardian, Campus Pi and the universities has gone into trying to match them up. One size does not fit all, as we have learned the hard way.

Last year we used student numbers derived from Joint Academic Coding System (JACS) codes (the Hesa subject classifications) to calculate spend per student last year. This was strongly criticised and this year, thanks to more detailed data being available from Hesa, we can use cost centre level FTEs in the spending and SSR measures which we hope will be welcomed as an improvement.

Job prospectsBased on the 2004-05 Destinations of Leavers from HE Return, we assess the proportion of graduates who find graduate-level employment, or study full time, within six months of graduation. This measure relates to populations of at least 10 students.

Value added Our attempt is to measure how well universities teach a wide range of students, not just the superstars. Scores have been revamped for this year's table, and now employ a sophisticated methodology that tracks individual students from enrolment to graduation, comparing qualifications upon entry with the award that a student receives at the end of their studies.

Each student is given a probability of achieving a first or 2:1, based on the qualifications that they enter with. If they manage to earn a good degree then they score points which reflect how difficult it was to do so (in fact, they score the reciprocal of the probability of getting a 1st or 2:1). Thus an institution that is adept at taking in students with low entry qualifications and converting them into graduates with the best degrees will score highly in the value-added measure, since the number of students getting a 1st or 2:1 will have exceeded statistical expectations. At least 10 students must be in a subject.

Entry scoreDetermined by taking the average tariff points of first-year first degree entrants to a subject. Because of the way in which core skills and key skills are treated in the tariff calculations of the UK countries, tariffs for Scottish institutions have been assessed separately. There must be at least eight students in this measure.

Tariff bandsThese have been dropped from this year's tables for ease of use.

Two universities - London Met and Keele - declined to provide data for these tables.

In the architecture subject table, the entry for Manchester/MMU denotes the joint architecture school, the Manchester School of Architecture, run by the University of Manchester and the Manchester Metropolitan University.

There are three joint medical schools: Brighton/Sussex, Hull/York, and the Peninsula medical school established by Exeter and Plymouth. These schools do not have individual institution profiles, but are linked from the tables through to the parent institution.

With regard to data provided by Hesa, it should be noted that Hesa cannot accept responsibility for any inferences or conclusions derived from the data by third parties.